Annankatu 18, P.O. Box 400, FI-00121 Helsinki, Finland | Tel. +358 9 686180 | Fax +358 9 68618210 | echa.europa.eu Committee for Risk Assessment RAC Annex 1 Background document to the Opinion proposing harmonised classification and labelling at Community level of Chlorobenzene EC Number: 203-628-5 CAS Number: 108-90-7 CLH-O-0000004060-90-03/D The background document is a compilation of information considered relevant by the dossier submitter or by RAC for the proposed classification. It includes the proposal of the dossier submitter and the conclusion of RAC. It is based on the official CLH report submitted to public consultation. RAC has not changed the text of this CLH report but inserted text which is specifically marked as ‘RAC evaluation’. Only the RAC text reflects the view of RAC. Adopted 14 March 2014
ANNEX 1 - BACKGROUND DOCUMENT TO RAC OPINION ON CHLOROBENZENE
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CONTENTS
Part A.
1 PROPOSAL FOR HARMONISED CLASSIFICATION AND LABELLING ................................................. 4
1.1 SUBSTANCE ........................................................................................................................................................... 4 1.2 HARMONISED CLASSIFICATION AND LABELLING PROPOSAL .................................................................................. 4 1.3 PROPOSED HARMONISED CLASSIFICATION AND LABELLING BASED ON CLP REGULATION AND/OR DSD CRITERIA
6
2 BACKGROUND TO THE CLH PROPOSAL ..................................................................................................... 9
2.1 HISTORY OF THE PREVIOUS CLASSIFICATION AND LABELLING .............................................................................. 9 2.2 SHORT SUMMARY OF THE SCIENTIFIC JUSTIFICATION FOR THE CLH PROPOSAL .................................................... 9 2.3 CURRENT HARMONISED CLASSIFICATION AND LABELLING .................................................................................... 9
2.3.1 Current classification and labelling in Annex VI, Table 3.1 in the CLP Regulation .................................. 9 2.3.2 Current classification and labelling in Annex VI, Table 3.2 in the CLP Regulation ................................ 11
2.4 CURRENT SELF-CLASSIFICATION AND LABELLING ............................................................................................... 11 2.4.1 Current self-classification and labelling based on the CLP Regulation criteria ...................................... 11 2.4.2 Current self-classification and labelling based on DSD criteria .............................................................. 12
3 JUSTIFICATION THAT ACTION IS NEEDED AT COMMUNITY LEVEL .............................................. 12
SCIENTIFIC EVALUATION OF THE DATA ........................................................................................................... 13
1 IDENTITY OF THE SUBSTANCE .................................................................................................................... 13
1.1 NAME AND OTHER IDENTIFIERS OF THE SUBSTANCE ............................................................................................ 13 1.2 COMPOSITION OF THE SUBSTANCE ...................................................................................................................... 14
1.2.1 Composition of test material ..................................................................................................................... 14 1.3 PHYSICO-CHEMICAL PROPERTIES ........................................................................................................................ 14
2 MANUFACTURE AND USES ............................................................................................................................ 18
3 CLASSIFICATION FOR PHYSICO-CHEMICAL PROPERTIES ................................................................ 19
4 HUMAN HEALTH HAZARD ASSESSMENT .................................................................................................. 19
4.1 TOXICOKINETICS (ABSORPTION, METABOLISM, DISTRIBUTION AND ELIMINATION) ............................................. 19 4.1.1 Non-human information ............................................................................................................................ 19 4.1.2 Human information ................................................................................................................................... 20 4.1.3 Summary and discussion on toxicokinetics ............................................................................................... 20
4.2 ACUTE TOXICITY ................................................................................................................................................. 21 4.3 SPECIFIC TARGET ORGAN TOXICITY – SINGLE EXPOSURE (STOT SE).................................................................. 24 4.4 IRRITATION ......................................................................................................................................................... 24 4.5 CORROSIVITY ...................................................................................................................................................... 28 4.6 SENSITISATION .................................................................................................................................................... 28 4.7 REPEATED DOSE TOXICITY .................................................................................................................................. 29 4.8 SPECIFIC TARGET ORGAN TOXICITY (CLP REGULATION) – REPEATED EXPOSURE (STOT RE) ............................ 29 4.9 GERM CELL MUTAGENICITY (MUTAGENICITY) .................................................................................................... 29 4.10 CARCINOGENICITY ......................................................................................................................................... 29 4.11 TOXICITY FOR REPRODUCTION ....................................................................................................................... 29 4.12 OTHER EFFECTS .............................................................................................................................................. 29
6 OTHER INFORMATION .................................................................................................................................... 29
Chlorobenzene is eliminated in the form of metabolites, principally in the urine and to a smaller
extent in the faeces as well. Unmetabolized chlorobenzene is mainly exhaled via the lungs.
Moreover, it could be demonstrated, that the metabolism of chlorobenzene is saturated at repeated
and high doses.
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4.2 Acute toxicity
4.2.1 Acute toxicity: oral.
Not evaluated in this dossier.
4.2.2 Acute toxicity: dermal.
Not evaluated in this dossier.
4.2.3 Acute toxicity: inhalation
4.2.3.1 Non-human information.
The results of relevant inhalation acute toxicity studies are summarized in Table 12.
Table 12: Overview of experimental data on acute inhalation toxicity.
Method Results Remarks Reference
Test animals:
rat, male/female
Inhalation Hazard Test
GLP: no data
OECD Guideline 403 (Acute
Inhalation Toxicity)
Deviations: yes
For each exposure time only 3
animals of each sex were used
instead of 5 for each sex.
Analytical purity not reported.
Housing condition of the animals
was not reported.
LC50 = 66 mg/l/ (1.8h/4h) =
29.7 mg/L
2 (reliable with
restrictions)
Key study
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
Klimisch, H.J.
(1988)
Test animals:
rats
Strain: Sprague-Dawley
Sex: male
Route of administration:
inhalation: vapour
Well documented study,
comparable to guideline study
(OECD Guideline 403 Acute
Inhalation Toxicity)
Non- GLP study
Rats were exposed to
concentrations ranging from 2000
to 3500 ppm (9.17 - 13.6 mg/l)
over 6 hours. Vapour was
generated at 24°C, 50 % relative
humidity. Rats were observed for
14 days.
LC50 (male): 13.6 mg/l (2965
ppm)
2 (reliable with
restrictions)
Key study
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
purity unknown
Bonnet, P. et al.
(1982)
Test animals:
rats LC50 (approximately): 14.1 mg/l 3 (not reliable) De Jongh J et al.
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Sex: no data
Route of administration:
inhalation: vapour
GLP: no data
Guidline: no guideline followed
Exposure duration: 6 hours
(3000 ppm) Key study
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
purity unknown
(1998)
4.2.3.2 Acute toxicity: Human information
No data available.
4.2.4 Acute toxicity: other routes Not evaluated in this dossier.
4.2.5 Summary and discussion of acute toxicity
The experimental studies which was used by dossier submitter in order to evaluate acute inhalation
toxicity of chlorobezene are mentioned in Table 12. Ideally, classification should be achieved using
data generated from studies conducted in accordance with officially adopted OECD test guidelines.
According to the Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation
(EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation,
Authorisation and Restriction of Chemicals (REACH), the acute inhalation toxicity should be
performed according to the B.2 method. For all studies mentioned in Table 12 there are some
deviations from B.2 method. The study performed by Klimisch (1988) was performed in
accordance with OECD Guideline 403 but for each exposure time only 3 animals of each sex were
used instead of 5 for each sex. The study performed by Bonnet (1982) is comparable to OECD
Guideline study. The exposure time in each study mentioned in Table 12 was different than
exposure time required in B.2 method (4 hours). The LC50 value mentioned in Table 12 were
calculated for 1.8 hours exposure (Klimisch; 1988) and for 6 hours exposure (Bonnet; 1982 and De
Jongh, 1988).
In principle, the classification criteria for acute inhalation toxicity relate to a 4-hour experimental
exposure period. If data for a 4-hour period are not available then extrapolation of the results to 4
hours are often achieved using Haber’s Law (C.t = k). However, there are limits to the validity of
such extrapolations, and it is recommended that the Haber’s Law approach should not be applied to
experimental exposure durations of less than 30 minutes or greater than 8 hours in order to
determine the 4-hour LC50 for C&L purposes (ECHA: Guidance on information requirements and
chemical safety assessment. Chapter R.7a: Endpoint specific Guidance).
Nowadays a modification of Haber’s Law is used (Cn.
t = k) as for many substances it has been
shown that n is not equal to 1 (Haber’s Law). In case extrapolation of exposure duration is required,
the n value should be considered. If this n value is not available from literature, a default value may
be used. It is recommended to set n = 3 for extrapolation to shorter duration than the duration for
which the LC50 or EC50 was observed and to set n = 1 for extrapolation to longer duration), also
taking the range of approximately 30 minutes to 8 hours into account.
The LC50 (for a 4-hour periof of exposure) was calculated, by dossier submitter, according to the
modified Haber's rule. The following value of LC50, for 4 hours exposure, was obtained:
LC50 = 29,6 mg/l (for study performed by Klimisch),
LC50 = 15,5 mg/l (for study performed by Bonnet),
LC50 = 16,1 mg/l (for study performed by De Jongh J.).
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It should be noted that two of the above mentioned values of LC50 are appriotiate for classification.
4.2.6 Comparison with criteria
The lowest LC50 values for chlorobenzene are 15,5 mg/l (Bonnet’s study) and 16,1 mg/l (study
performed by De Jongh J.).
According to the CLP chlorobenzene should be classified as Acute Tox Cat. 4 because the LC50 is
within the limits, 10,0 < ATE ≤ 20,0 (vapours, mg/l). Therefore the minimum classification Acute
Tox. Cat 4*, is considered no longer necessary.
The current classification according to 67/548/EEC remains unchanged. According to 67/548/EEC
chlorobenze should be classified as Xn; R20 because the LC50 inhalation, rats, for gases, vapours, is
within the limits, 2,0 < LC50 ≤ 20,0 mg/l/4h.
4.2.7 Conclusions on classification and labelling for acute toxicity
According to CLP regulation requirements chlorobenzene should be classified as Acute Tox. Cat. 4
with hazard statement H332 (Harmful if inhaled).
According to DSD requirements chlorobenzene should be classified as harmful with risk phrase
R20 (Harmful by inhalation).
RAC evaluation of acute toxicity
Summary of the Dossier submitter’s proposal The dossier submitter (DS) provided an overview of the toxicokinetic data and
summarised the results from available acute inhalation studies.
For acute inhalation toxicity in rats, the dossier submitter concluded that the lowest LC50
values for chlorobenzene are 15,5 mg/l (Bonnet et al, 1982) and 16,1 mg/l (De Jongh,
1998). According to the CLP Regulation, chlorobenzene should be classified as Acute Tox
Cat. 4 because the LC50 is within the range 10,0 < ATE ≤ 20,0 (vapours, mg/l).
Therefore the minimum classification Acute Tox. Cat. 4*, is considered no longer
necessary.
Comments received during public consultation Five member states supported the proposed classifications as specified in the dossier.
One member state stated that the CLH report would had benefitted from more details on
the method and observed effects and indicated that in one study the reported LC50 of
16,1 mg/l was based on a PB-PK model using LC50 values retrieved from literature (De
Jongh, 1998).
Additional key elements Additional information on the mouse was found in a hazard assessment report from the
Chemicals Evaluation and Research Institute (CERI), Japan (2007). The LC50 value for
this species was 8.8 mg/l (1889 ppm) after a 6 hour exposure time. The corresponding
4h-LC50 value using the Haber’s Law extrapolation was 10.07 mg/l. No further
information was given in this report. The same information was found in a report from the GDCh BUA (1990) with the study of Bonnet et al. (1982) identified as the source.
Assessment and comparison with the classification criteria
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RAC in general agrees with the dossier submitter’s conclusion on the classification on
acute inhalation toxicity.
The CLH report summarises results from three acute inhalation studies that were
identified by the dossier submitter as key studies. Two of these studies were assessed by
the DS as being compliant with OECD TG 403. In fact, none of the studies was in full
agreement with the guideline test design. Information on the purity of the test substance
was lacking in all studies. Exposure durations were shorter or longer than the 4 h
standard exposure time and all LC50 values were extrapolated to a 4h LC50 value. The test
groups in one study included 3 (instead of 5) animals/sex. In the end, the calculated LC50
values of all studies were in the same size range (15.5 mg/l, 16.1 mg/l, 29.7 mg/l).
The small differences in LC50 values between the two guideline-compliant studies provide
evidence that these values may be relied on for the purpose of classification. However,
the information on the LC50 from the Klimisch (1988) study is very scarce. The only
information on observed effects that is given in this publication is that an LT50 value (the
time of exposure after which 50% of the animals died) was 1.8 hours at a nominal
concentration of 66 mg/l chlorobenzene (corresponding to an extrapolated 4h value of
29.7 mg/l). As no information is given on whether other vapour concentrations were
tested and how many animals died after 1.8 h, it can not be excluded that the LC50 value
could actually be lower.
The lowest LC50 value of 15.5 mg/l (from Bonnet et al., 1982) is used for the
categorisation. This LC50 value is within the range of 10.0 < ATE ≤ 20.0 (vapours,
mg/ml), corresponding to Acute Tox. 4.
The published LC50 value for mice is also consistent with the Acute Tox. 4 category
criteria.
RAC agrees with the proposal to remove the reference indicating minimum classification
for Acute Tox. 4 for the inhalation route. According to the CLP regulation, chlorobenzene
should be classified as Acute Tox. 4, H332 (Harmful if inhaled).
4.3 Specific target organ toxicity – single exposure (STOT SE)
Not evaluated in this dossier.
4.4 Irritation
4.4.1 Skin
4.4.1.1 Non-human information
The primary irritant/corrosive effect of pure chlorobenzene, has been tested on rabbit skin according
to OECD Guideline for Testing of Chemicals No. 404 referenced as Method B4 (“Acute toxicity:
Dermal Irritation/Corrosion”) in Commission Regulation (EC) No 440/2008 without deviations
(Suberg, H. (1983a)).
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Table 13: Overview of experimental data on skin irritation.
Method Results Remarks Reference
Test animals:
Species: Rabbits
Strain: New Zeland White
OECD Guideline for Testing of
Chemicals No. 404" without
deviations
Environmental conditions
Temperature: 19 – 25°C
Humidity: 40 – 60%
Photo period: 12 hrs dark / 12 hrs
light
irritant
The primary irritant/corrosive
effect of pure chlorobenzene,
has been tested on rabbit skin
according to "OECD Guideline
for Testing of Chemicals No.
404" without deviations.
3 New Zealand White rabbits
have been tested with 0.5 mL of
pure chlorobenzene for 4 hour-
exposure followed by a post
expsoure period of 14 days.
The evaluation was performed
according to Draize.
1 (reliable without
restrictions)
Key study
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
purity unknown
Suberg, H.
(1983a)
Test animals:
Species: Rabbits
Strain: no data
GLP – no (was not mandatory as
of time when study was
performed)
Comparable to guideline study
(OECD Guideline for Testing of
Chemicals No. 404) but with
acceptable restrictions (no data on
purity of the substance, no GLP)
Before OECD Guideline 404 was
established, skin irritation was
tested using an internal BASF
method.
irritant (according to registrants)
The BASF scoring system was
converted to the scoring system
by Draize. Scoring of skin
changes was performed as
following: day of application,
then after 24h, 48h, 72h, 6d, 8d,
10d, 13d, 15d, 17d, and 20d.
2 (reliable with
restrictions)
Key study
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
purity unknown
Company data
(BASF AG)
(1960)
Test animals:
Species: no data
Strain: no data
Type of method: no data
Test guideline: no guideline
followed
Slight reddening of the skin was
observed from application of
chlorobenzene either on the
uncovered or covered skin.
Continous contact for a week
may result in moderate erythema
and slight superficial necrosis.
4 ( not assignable)
Only secondary
literature
Experimental result
Test material (EC
name):
chlorobenzene
CAS-No. 108-90-7
purity unknown
Irish, D.D. (1962)
In a primary dermal irritation study, three New Zealand White rabbits have been tested with 0.5 ml
of pure chlorobenzene to an area of approximately 2.5 cm x 2.5 cm for 4 hour-exposure followed
by a post exposure period of 14 days (Suberg, H. (1983a)). The evaluation was performed using the
scale included in B.4 Method “Grading of skin reaction” based on the scale of Draize.
All three animals showed marked erythema and oedema on the application sites. The intensity of
the skin reaction pertained the margins of the application sites. Until three days after the treatment
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skin desquamation was observed. No significant differences in skin reaction appeared among each
animals.
The skin findings were reversible in all animals within 6 days after removal of the patches.
The results of the skin findings are summarized in Table 14.
Table 14: Skin irritation scores following 4-h dermal exposure.
Readings Animal no Erythema Oedema
24 h 64 3 1
24 h 95 3 1
24 h 100 2 1
48 h 64 3 1
48 h 95 3 1
48 h 100 2 1
72 h 64 3 1
72 h 95 3 1
72h 100 2 1
Mean 24 -72h 64 3 1
Mean 24 -72h 95 3 1
Mean 24 -72h 100 2 1
Total mean
2.7 1
Mean scores over 24, 48, and 72 hours for each animal were 2.7 of max 4 for erythema and 1 of
max 4 for edema.
In the dossiers submitted by individual registrants there are also information on other skin
corrosion/irritation test (Company data (BASF AG); year of performence of test: 1960). The test is
comparable to guideline for this kind of study (B.3 or OECD) but with acceptable restrictions (no
data on purity of the substance, no GLP). Hovewer it should be underlined that GLP criteria were
developed in 90s Based on the results of the test (the oryginal BASF scoring system was converted
to the Draize scoring system used in the test guidance):
Irritation parameter: erythema score
Time point 24 and 48h
animal #1: Score 2
animal #2: Score 1.7
Max. score 4
Reversibility: fully reversible
Irritation parameter: edema score
Time point 24 and 48h
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animal #1: Score 0
animal #2: Score 1
Max. score 4
Reversibility: fully reversible
the registrants classify chlorobenzene as skin irritant.
4.4.1.2 Human information
The skin irritation properties of chlororbenzene were tested in 1 h dermal exposure experiment on
volunteers (Oettel, H. (1936)). Dermal exposure of 5 volunteers to chlorobenzene for 1 h resulted in
burning pain, hyperemia, whealing, and erythema formation at the application site. 12 hours
postexposure a minimal local vesiculation was seen. After a 5 hours exposure this effect was
slightly increased.
4.4.1.3 Summary and discussion of skin irritation
According to the results of the rabbit skin irritation study (Suberg, H. (1983a), chlorobenzene is
irritant to the intact shaved rabbit skin.
The study presented by individual dossier submitter (Company data (BASF AG); 1960) - there is no
enough information to conclude that based on that study chlorobenzene should be classified as skin
irritant.
4.4.1.4 Comparison with criteria
According to DSD requirements the substance is classified as skin irritant if:
- in the case where the B.4 test has been completed using three animals, either erythema and eschar
formation or oedema formation equivalent to a mean value of 2 or more calculated for each animal
separately has been observed in two or more animals.
According to CLP requirements the substance is classified as skin irritation category 2 if:
- mean value of ≥ 2.3 - ≤ 4.0 for erythema/ eschar or for oedema in at least 2 of 3 tested animals
from gradings at 24, 48 and 72 hours after patch removal or, if reactions are delayed, from grades
on 3 consecutive days after the onset of skin reactions.
4.4.1.5 Conclusions on classification and labelling
The decision on classification of chlorobenzene as skin irritant was based on test performed by
Suberg, H. (1983a). The test was performed according to OECD Guideline for Testing of
Chemicals No. 404. Mean scores over 24, 48, and 72 hours for each animal, obtained in above
mentioned test, were 2.7 of max 4 for erythema and 1 of max 4 for edema and the results meets the
criteria of classification of substances as skin irritant found in DSD and CLP.
According to DSD requirements chlorobenzene should be classified as skin irritant with risk phrase
R38 (Irritating to skin).
According to CLP regulation requirements chlorobenzene should be classified as skin irritation Cat.
2 with hazard statement H315 (Causes skin irritation).
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RAC evaluation of skin corrosion/irritation
Summary of the Dossier submitter’s proposal The dossier submitter gave an overview on the experimental studies on skin irritation.
Two studies were identified as key studies (Suberg, 1983a; BASF AG, 1960), but only the
Suberg study was compliant with OECD TG 404. Limitations were also reported for the
BASF study (no GLP, use of internal scoring system, only two animals). A third study
(Irish, 1962) was identified as not suitable for assessment (Klimish score of 4).
The dossier submitter concluded that the decision on classification of chlorobenzene as
skin irritant was based on the test performed by Suberg (1983a). The test was performed
according to OECD TG 404. The shaved skin of three rabbits were tested with 0.5 ml of
pure chlorobenzene for 4 h-exposure followed by a post-exposure period of 14 days.
Mean scores over 24, 48, and 72 hours for each animal, obtained in the above mentioned
test, were 2.7 of max 4 for erythema and 1 of max 4 for oedema and the results meets
the criteria for classification of the substance as skin irritant in the CLP Regulation.
The CLH report also documented skin irritation properties of chlororbenzene in 5
volunteers (Oettel, 1936). Dermal exposure for 1 h resulted in burning pain, hyperaemia,
whealing, and erythema formation at the application site. At 12 hours post-exposure,
minimal local vesiculation was seen. After 5 hours exposure this vesiculation was slightly
increased.
Comments received during public consultation Four member states supported the proposed classifications as specified in the dossier.
One member state did not comment on skin irritation.
Assessment and comparison with the classification criteria Based on the results from the study of Suberg (1983a), mean scores over 24, 48, and 72
hours from all 3 animals were 2.7 for erythema, and 2 out of 3 animals had erythema
scores of 3 at 24, 48, and 72 hours. All skin findings were reversible within 6 days after
the end of treatment. According to CLP classification criteria, a substance fulfills the
criteria for classification for skin irritation in category 2 (H315, Causes skin irritation) if
mean values of ≥2.3 - ≤4 for erythema/eschar or for oedema are observed in at least 2
of 3 tested animals from gradings at 24, 48 and 72 h after patch removal.
RAC agrees with the dossier submitter’s assessment that classification of chlorobenzene
as Skin Irrit. 2 according to the CLP Regulation is warranted.
4.4.1 Eye
Not evaluated in this dossier
4.5 Corrosivity
See section 4.4.
4.6 Sensitisation
Not evaluated in this dossier.
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4.7 Repeated dose toxicity
Not evaluated in this dossier.
4.8 Specific target organ toxicity (CLP Regulation) – repeated exposure (STOT RE)
Not evaluated in this dossier.
4.9 Germ cell mutagenicity (Mutagenicity)
Not evaluated in this dossier.
4.10 Carcinogenicity
Not evaluated in this dossier.
4.11 Toxicity for reproduction
Not evaluated in this dossier.
4.12 Other effects
Not evaluated in this dossier.
5 ENVIRONMENTAL HAZARD ASSESSMENT
Not evaluated in this dossier.
6 OTHER INFORMATION
One joint REACH registration dossier and two individual registration dossiers were available for
chlorobenzene when these CLH proposal was prepared. The information from REACH registration
dossiers were considered during preparation CLH proposal for chlorobenzene.
7 REFERENCES
BASF AG (1979). Raport no SIK-Nr. 78/1100 BASF, Department of Safty Engineering. BASF SE,
D-67056 Ludwigshafen.
BASF AG (1960). Abt. Toxikologie, Unveroeffentlichte Untersuchung, (X/44).
Beck U (1986). Chlorinated Hydrocarbons. In: Ullmann´s Encyclopedia of industrial chemistry,
